This invention relates to safety apparatus for hydraulic valves in dump body mechanisms in which the dump body is coupled to the hydraulic valve control member by a cable to automatically move the valve control member from its "raise" to its "neutral" position when the dump body reaches its uppermost position. In such dump body mechanisms, it is possible for a workman who may be working on the dump mechanism, underneath the raised dump body, to inadvertently bump into the cable and thus initiate an unwanted lowering of the dump body by exerting a pull on the valve control member from its "neutral" to its "lower" position.
The above-noted problem has been successfully overcome by a special hydraulic valve structure which is arranged to prevent a pull on the cable from moving the valve spool from its "neutral" to its "lower" position. This special hydraulic valve structure is disclosed in co-pending U.S. Pat. application Ser. No. 572,989. This structure is suitable for only a certain type of valve.
The principal object of this invention is to solve the above-noted problem with a simple and sturdy structure which is suitable for use with other valve mechanisms than that disclosed in said co-pending patent application.